Gregerson (hamstring) threw a bullpen session Thursday, Derrick Goold of the St. Louis Post-Dispatch reports.

EDGE Analysis

Assuming Gregerson's hamstring is OK when he's evaluated Friday, he should be cleared to head out on a minor-league rehab assignment with High-A Palm Beach. It's still unclear when he'll be ready to rejoin the big club, however, as the number of rehab appearances he'll make has yet to be determined. Gregerson is expected to slot into a setup role once healthy, with Greg Holland working as the team's closer.